This invention relates to radio frequency-transmissive compositions having reduced dissipation factors and methods of forming the same. The invention also concerns microelectronic devices, and in particular, wireless radio frequency communication devices which utilize such compositions, and methods of forming the same.
Some microelectronic devices are designed for wireless communication. Typically, such devices operate within a desired range of radio frequencies. In designing such devices, consideration must be given to the various materials which are utilized because of their potential to adversely impact device operation and performance. For example, some wireless microelectronic devices include antennas which are utilized to send and receive electronic signals which fall within the desired range of frequencies. These antennas can be covered with a material which serves to protect the antenna from the external environment. Yet in protecting the antenna, such materials by virtue of their physical characteristics may undesirably affect the ability of the device (and antenna) to transmit and receive electronic signals within the desired range of radio frequencies, i.e. such material may cause the signals to be attenuated or undesirably dissipated. Such materials can also affect the electromagnetic characteristics of such antennas such as the antenna""s resonant frequency.
Some microelectronic communication devices are very small and can be covered with a protectant which effectively seals the device. As with those materials which can adversely affect an antenna""s operation by covering all or a portion thereof, such protectants can also have an impact on overall device operation. Thus it is not enough to select a protectant which only serves to protect or seal the device. Rather, the designer must consider all of the operation-impacting ramifications of a particular material when it is selected for use with a particular device.
This invention arose out of concerns associated with providing materials and methods of forming materials which have desirable radio-frequency characteristics. This invention also arose out of concerns associated with providing microelectronic devices, and in particular, wireless radio frequency communication devices which utilize such materials, and methods of forming the same.
Radio frequency-transmissive compositions having reduced dissipation factors, microelectronic devices, and in particular, wireless radio frequency communication devices which utilize such compositions, and methods of forming the same are described. In one implementation, a liquid resin is provided and a solid organic polymer filler material is provided within the resin to impart a degree of radio frequency transmissivity which is greater than that of the resin alone, i.e. the composition has a reduced dissipation factor. An exemplary resin comprises epoxy and an exemplary filler material is a polytetrafluoroethylene powder. In another implementation, such composition is formed or applied over a substrate which includes an antenna formed thereon and cured to provide a solid coating. The substrate can also have integrated circuitry and a battery mounted thereon to provide a wireless communication device. In such a case, the composition can be formed over and cured atop the integrated circuitry and the battery.